Pull out all the stones and stuff steal wool in the gas lines coming up from the basement.

@Amy Arata Here is a link to Rock Wool's DIY video outlining a good soundproofing system.

Cotton towels.

I use a 70/30 Cotton/Poly blend.

Also go seal all cracks/holes on the exterior with steel wool and caulk.

I think your contractor is trying to pull the wool of your eyes. 

I thought this was about food carts, those things you push in a grocery store.....Now I get it, you're talking about consession stands/trailers, like at the state fair with cotton candy....?

Replacing the 1950's R5 paper-backed rock wool insulation in the walls with R24 worth of closed-cell spray foam; adding 6" of blown cellulose to the attic (to bring it to R50); installing an R10 subfloor over the slab; and installing a ductless split heat pump cost us ~8K.

We use cedar in closets where wool items are stored as it does have some properties than repel insects.

I let set at least 24 hours before applying finishing clear coat or wax;Vac the entire room, wipe the floor, walls, woodwork and ceiling , I know, extreme, but there will be no dust to settle on the floor for pre stain and clear coats, I use a cotton T-shirt as a cleaning rag, prevents lint you may get from other rags. :)